Home > Publications database > Reactions between nitrite and soil organicmatter and their role in nitrogen trace gasemissions and nitrogen retention in soil |
Book/Dissertation / PhD Thesis | FZJ-2018-02854 |
2018
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
ISBN: 978-3-95806-299-3
Please use a persistent id in citations: http://hdl.handle.net/2128/18486 urn:nbn:de:0001-2018050906
Abstract: As a key intermediate of both nitrification and denitrification, nitrite (NO$_{2}^{‒}$) is highly chemically reactive to soil organic matter (SOM), and it was proved previously that considerable amounts ofnitrogen (N) trace gases, including nitrous oxide (N$_{2}$O) and nitrogen oxides (NO$_{x}$), were produced from the reactions of NO$_{2}^{‒}$ with SOM in chemical assays decades ago. However, the role of NO$_{2}^{‒}$‒SOM reactions in nitrogen trace gas emissions and nitrogen retention in soils has been neglected until recently. It is vital to identify and quantify major sources and sinks of nitrogen trace gases for the sake of the environment. On the other hand, better understanding of N$_{2}$O sources and nitrogen retention is also essential to improve the nitrogen use efficiency and soil fertility in agriculture. Therefore, this thesis aimed to gain a better understanding of the contribution of NO$_{2}^{‒}$‒SOM reactions to nitrogen trace gas emissions and nitrogen retention in soil. Emissions of N$_{2}$O and carbon dioxide (CO$_{2}$) from the reactions of NO$_{2}^{‒}$ with lignin and ligninderivatives (4‐hydroxybenzoic acid, 4‐hydroxybenzaldehyde, 4‐hydroxy‐3‐methoxybenzoic acid, 4‐hydroxy‐3‐methoxybenzaldehyde, 4‐hydroxy‐3,5‐dimethoxybenzoic acid, 4‐hydroxy‐3,5‐dimethoxybenzaldehyde), as well as N$_{2}$O isotopic signatures, were studied in chemical assays at pH 3‒6. Among the six tested lignin derivatives, the highest N$_{2}$O emission was found in the 4‐hydroxy‐3,5‐dimethoxybenzaldehyde treatment, and the dependency of N$_{2}$O and CO$_{2}$ on pH varied according to the structures of the organic substances. Most interestingly, N$_{2}$O $^{15}$N site preference (SP) varied largely from 11.9‒37.4 ‰ depending on pH and structures of lignin derivatives, which was undistinguishable from other N$_{2}$O sources, such as nitrification, denitrification, and abiotic hydroxylamine oxidation. Furthermore, real‐time N$_{2}$O isotopic characterization revealed that SP also shifted largely during the reaction of NO$_{2}^{‒}$ with lignin derivatives. Hyponitrous acid and nitramide pathways, which could be responsible for N$_{2}$O formation, were proposed to explain the shift of N$_{2}$O SP values. [...]
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